Deflectable interstitial ablation device

ABSTRACT

A deflectable interstitial ablation device includes an elongated housing, an electrode mounted within the elongated housing, a driver coupled to the electrode, an imaging device integrally mounted within the elongated housing and a deflection system disposed within the elongated housing. The elongated housing has a proximal end, a distal end, and a deflectable segment. The electrode is deployable from a first position within the elongated housing to a second position a predetermined distance beyond the distal end of the elongated housing. The electrode further has a flexible portion capable of deflecting with the deflectable segment of the elongated housing, and can be deployed by the driver with a sufficient force such that penetration of the urethral wall occurs in a single motion. The imaging device further has a flexible portion capable of deflecting with the deflectable segment of the elongated housing. The deflection system has a proximal end in communication with a steering mechanism, for controllably deflecting the deflectable segment of the elongated housing by any angle. The deflection of the deflectable segment allows deflection of the electrode and the imaging device, thus facilitating proper placement of the electrode.

This application is a continuation of U.S. patent application Ser. No.10/004,759, filed on Dec. 4, 2001, now U.S. Pat. No. 6,482,203, which isa continuation of U.S. patent application Ser. No. 09/661,835, filed onSep. 14, 2000, now U.S. Pat. No. 6,352,534, which is a continuation ofU.S. patent application Ser. No. 08/940,519, filed on Sep. 30, 1997, nowU.S. Pat. No. 6,238,389. The disclosures of each of the aboveapplications are incorporated by reference in their entirety.

FIELD OF THE INVENTION

The invention relates to an interstitial ablation device and method forperforming tissue ablation, and in particular, to an improvedinterstitial ablation device providing enhanced electrode placement andcontrol.

BACKGROUND

Ablation devices can be used to treat tumors in the body. In particular,ablation devices can be used to treat benign prostatic hypertrophy orhyperplasia (BPH), a condition resulting in an enlargement of theprostate gland. This is a common medical problem typically experiencedby men over 50 years of age. Hyperplastic enlargement of the prostategland often leads to compression of the urethra, which results inobstruction of the urinary tract.

An ablating needle can be used with a cystoscope to treat BPH byablating a prostatic adenoma, which is a benign tumor inside theprostate. To perform the ablation procedure, a physician inserts adistal end of the cystoscope into the urethra of a patient while viewingthe advance through an eye piece of the cystoscope. The needle electrodeis also introduced into the urethra through a working channel of thecystoscope. The cystoscope and the needle electrode are typicallyintroduced inside the urethra sequentially. The distal end of the needleelectrode is positioned adjacent the prostate near the prostaticadenoma. The physician then causes the needle electrode to penetrate theurethral wall, such that it is positioned inside the prostatic adenoma.Radiofrequency (RF) energy is applied to the needle electrode tocoagulate tissue surrounding the electrode. Coagulation causes necrosisof the prostatic adenoma, resulting in atrophy of the prostate and areduction in the compressive forces that interfere with urine flowthrough the urethra.

During the ablation procedure, it is important that the needle electrodebe positioned precisely, because inaccurate electrode placement cancause incontinence in the patient. Visualization is typically providedby inserting the needle electrode through a cystoscope. One disadvantageof the ablation device insertable through a cystoscope is that it isdifficult to feed the device through a working channel of the cystoscopeand requires a lot of juggling which can make accurate placement of theneedle electrode difficult. Moreover, it is often difficult to observethe distal tip of the needle electrode as the electrode penetrates theurethral wall, because the distal end of the electrode is typicallydeflected in order to penetrate the urethral wall while the viewingdevice itself does not deflect along with the needle electrode.

Existing interstitial ablation systems are also uncomfortable for thepatients and cumbersome for the physician performing the procedure. Mostcystoscopes and ablation systems integrating imaging devices tend to berigid and uncomfortable for patients when inserted through a body lumensuch as the urethra. The systems also have numerous knobs and dials thatthe physician must adjust for controlling needle deployment, fluidintroduction, and application of RF energy.

Thus, there remains a need for an interstitial ablation device thatprovides accurate electrode placement and better control of theelectrode, reduces patient discomfort and simplifies the process ofperforming ablation.

SUMMARY OF THE INVENTION

In one aspect, the invention features a deflectable interstitialablation device. In one embodiment, the device includes an elongatedhousing, an electrode mounted within the elongated housing, a drivercoupled to the electrode, an imaging device integrally mounted withinthe elongated housing, and a deflection system disposed within theelongated housing. The elongated housing has a proximal end, a distalend, and a deflectable segment. The electrode is deployable from a firstposition within the elongated housing to a second position apredetermined distance beyond the distal end of the elongated housing,and has a flexible portion capable of deflecting with the deflectablesegment of the elongated housing. The driver exerts a force sufficientto drive the electrode from the first position to the second position ina single motion. The imaging device has a flexible portion capable ofdeflecting with the deflectable segment of the elongated housing. Thedeflection system controllably deflects the deflectable segment of theelongated housing to a desired angle. The deflection system has aproximal end in communication with a steering mechanism.

In one embodiment, the imaging device includes a plurality ofillumination optical fibers and a plurality of viewing optical fibersextending from the proximal end to the distal end of the elongatedhousing. The viewing optical fibers can comprise a fused bundle ofviewing optical fibers surrounded by illumination optical fibers,wherein the viewing optical fibers are in communication with a lensdisposed at the distal end of the elongated housing. In anotherembodiment, the electrode is a hollow needle electrode and an insulationsheath surrounds the needle electrode. The needle electrode and theinsulation sheath are individually and slidably mounted inside theelongated housing, such that the insulation sheath is capable ofcovering a proximal portion of the needle electrode which extends beyondthe distal end of the elongated housing. In still another embodiment,the driver coupled to the electrode can exert a force within the rangeof ¼ lb to 1 lb to drive the electrode from the first position to thesecond position in a single motion.

In another embodiment, the device includes an elongated housing, anelectrode mounted within the elongated housing, an imaging deviceintegrally mounted with the elongated housing, a deflection systemdisposed within the elongated housing, and a foot pedal for deployingthe electrode.

In another aspect, the invention features a method for treating tissue.A deflectable interstitial ablation device is inserted into a body lumenwhich provides access to the tissue to be treated. The deflectableinterstitial ablation device includes an elongated housing having adeflectable segment, a deployable electrode mounted within the elongatedhousing, a driver coupled to the electrode for exerting a force to drivethe electrode, an imaging device integrally mounted with the elongatedhousing, and a deflection system disposed within the elongated housing.The distal end of the elongated housing is positioned near the tissue.The deflectable segment of the elongated housing is deflected toward thetissue, thereby deflecting the electrode and the imaging device towardthe tissue along with the deflectable segment. The electrode is deployedto penetrate a wall of the lumen and to position a distal end of theelectrode adjacent the tissue. Radio frequency energy is applied to theelectrode in an amount and for a duration sufficient to ablate thetissue.

In one embodiment, an insulation sheath is deployed to cover a proximalportion of the deployed electrode to protect the wall of the lumen fromdirectly contacting the needle electrode during the treatment. Inanother embodiment, a balloon disposed on a body of the elongatedhousing of the deflectable interstitial ablation device is inflated tosecure the position of the elongated housing inside the lumen. In yetanother embodiment, a basket disposed on a body of the elongated housingof the deflectable interstitial ablation device is expanded to secure aposition. In still another embodiment, the distal end of the elongatedhousing is connected to an actuator in communication with a foot pedaland the foot pedal is depressed to deploy the electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described with particularity in the appended claims.The above and further advantages of this invention may be betterunderstood by referring to the following description taken inconjunction with the accompanying drawings.

FIG. 1A shows a side view of a deflectable interstitial ablation deviceaccording to one embodiment of the invention.

FIG. 1B shows a portion of the deflectable insterstital ablation devicehaving a basket for maintaining the placement of the device in a bodylumen, according to one embodiment of the invention.

FIG. 2 illustrates a deflecting segment of the deflectable interstitialablation device of FIG. 1A.

FIG. 3 shows a cross sectional view of the deflectable interstitialablation device of FIG. 1A cut through lines 3′-3″.

FIG. 4 shows a cross sectional view of a distal end of the deflectableinterstitial ablation device of FIG. 1A cut through lines 4′-4″.

FIG. 5A is a side view of a kinetically deployable needle electrodeaccording to one embodiment of the invention.

FIG. 5B is a cross sectional view of the kinetically deployable needleelectrode of FIG. 5A prior to deployment.

FIG. 5C is a cross sectional view of the kinetically deployable needleelectrode of FIG. 5A in a loaded position.

FIG. 5D is a cross sectional view of the kinetically deployable needleelectrode of FIG. 5A with the needle electrode deployed.

FIG. 5E is a cross sectional view of the kinetically deployable needleelectrode of FIG. 5A with the needle electrode and the insulation sheathdeployed.

FIG. 6 shows a transurethral interstitial ablation system employing afoot pedal according to one embodiment of the invention.

FIG. 7 shows an actuator for deploying a needle electrode according toone embodiment of the invention.

DETAILED DESCRIPTION

Referring to FIGS. 1A and 4, a deflectable interstitial ablation device10 includes an elongated housing 12, an electrode 14 extending withinthe elongated housing 12, an imaging device 16 integrally mounted withthe elongated housing 12 and a deflection system 18 disposed within theelongated housing 12. The electrode 14 can comprise a needle electrodehaving a sharpened tip, or an electrode having a blunt tip. Theelongated housing 12 has a proximal end, a distal end and a deflectablesegment 22 further as further shown in FIG. 2. The elongated housing 12can be constructed to be flexible so that the housing 12 may be insertedinto the urethra without much discomfort. In one embodiment, the housing12, can be, for example, a flexible multi-lumen catheter. In anotherembodiment, the housing 12, can be, for example, a substantially rigid,single lumen catheter having a deflectable segment 22. In one detailedembodiment, the housing 12 can have a diameter from about 15 to 16French. It is to appreciated that the diameter of the housing 12 canvary depending on the intended use of the ablation device 10.

In order to provide accurate placement of the electrode 14 inside theurethra, the present invention further provides means for stabilizingthe position of the device 10 before deploying the electrode 14. In oneembodiment, the elongated housing 12 of the invention includes a balloon24 for securing the position of the device 10 while the electrode 14 isdeployed at the ablation site. The elongated housing 12 includes a fluidport with a luer fitting 26 for introducing a fluid such as, forexample, air or water for inflating the balloon 24. The fluid enters theballoon 24 through an inflation sleeve further shown in FIG. 2 toinflate the balloon 24. Another advantage provided by the balloon 24 isthat the balloon 24 can block the blood vessels on the urethral wall andslow down heat conduction provided by the blood vessels. In oneembodiment, the balloon 24 is compliant enough to fit inside theurethra. In one detailed embodiment, the balloon is constructed of latexor silicone. The diameter of the inflated balloon, in one embodiment,can be about 30 French.

In another embodiment, as shown in FIG. 1B, the elongated housing 12 caninclude a basket 25 to stabilize the device 10 position duringdeployment of the electrode 14. The basket 25 can comprise a wire meshattached to an outer surface of the housing 12 surrounding the electrode14, the imaging device 16 and the deflection system 18. The housing 12can further be surrounded by an elongated sheath or catheter 27 suchthat the wire mesh comprising the basket 25 remains retracted duringplacement of the device and expands into the basket 25 shown in FIG. 1Bto secure the position and placement of the electrode 14 after theelectrode 14 has been exposed.

As shown, the proximal end of the elongated body 12 is in communicationwith a detachable eye piece coupler 28. A detachable eye piece 30 iscoupled to the eye piece coupler 28, and the physician observesinsertion of the device 10 into the urethra and the electrode 14deployment by looking into the eye piece 30.

The proximal end of the elongated body 12 is also in communication witha handle 32. The handle 32 includes a slide member 34 for controllingdeployment of the electrode 14. In one embodiment, the handle 32 caninclude two slide members (not shown), one for controlling the movementof the electrode 14 and the other for controlling the movement of theinsulation sheath 40. In another embodiment, the slide member 34 cancontrol the movement of the electrode 14 and the insulation sheath 40secured to the electrode 14, to expose a predetermined amount of theelectrode 14. As shown, the handle 32 also includes an electricalconnector 38 for coupling the proximal end of the electrode 14 to apower source (not shown). In a preferred embodiment, the power source isan RF generator, however it is to be appreciated that other energysources can be used, such as a microwave generator. The handle 32further includes a luer port 36 for injecting fluid and an irrigationport 31 for removing fluid. In one embodiment, the fluid can be aconductive fluid for improving ablation procedures. Conductive fluids,can include, for example, saline and lydocaine. The use of a conductingfluid prevents desiccation of tissue and prevents an increase in theimpedance during the ablation procedure.

Referring to FIG. 2, the electrode 14 can be deployable from a firstposition within the elongated housing 12 to a second position beyond thedistal end of the elongated housing 12 as shown. In one embodiment, theelectrode 14 deploys to a predetermined distance beyond the distal endof the elongated housing 12. It is to be appreciated that the distancethe electrode 14 deploys can vary depending on the intended application.As shown, the electrode 14 also has a flexible portion 40 a whichdeflects along with the deflectable segment 22 of the elongated housing12. In one detailed embodiment, the deflectable segment 22 is located atthe distal end of the elongated housing 12 and has a dimension of fromabout 2.5 cm to about 4.5 cm measured from the distal end of the housing12. It is to be appreciated that the length of the deflectable segment22 can fall outside of the above range, depending on the intendedapplication of the device 10. In one embodiment, the dimension andposition of the flexible portion 40 a of the electrode 14 corresponds tothat of the deflectable segment 22 of the elongated housing 12.Referring to FIG. 2, illustrated in phantom in a deflected position, isthe deflectable segment 22 and electrode's flexible portion 40 a at thedistal tip of the elongated housing 12.

Referring to FIGS. 2 and 3, the electrode 14 can be a needle electrodesurrounded by an insulation sheath 40. The needle electrode 14 and theinsulation sheath 40 are placed inside an electrode guide tube 41disposed inside the elongated housing 12. The insulation sheath 40, forexample, may be constructed from an insulating polymer material such aspolyimide. In another embodiment, the needle electrode 14 can be coatedwith an insulator, such as Teflon or ceramic. The needle electrode 14and the insulation sheath 40 can be individually and slidably mountedinside the elongated housing 12, such that the insulation sheath 40 iscapable of covering a proximal portion of the needle electrode 14extending beyond the distal end of the elongated housing 12. Byadjustably covering a proximal portion of the electrode 14 with theinsulation sheath 40, the physician can control the amount of electrode14 that is exposed, and thus control the conductive region andconsequently, the size of the ablation area. This feature is importantin transurethral interstitial ablation of prostate tissue, becauseurethral walls can be protected from being ablated during the procedure.Alternatively, the insulation sheath 40 can be fixed to a proximalportion of the needle electrode 14 and the needle electrode 14 can beslidably mounted inside the elongated housing 12. In another embodiment,as shown in FIG. 3, the electrode 14 can comprise a hollow electrode 14including a passageway 43. In one embodiment, the hollow electrode 14has an inner diameter of approximately 0.011 inches and an outerdiameter of approximately 0.02 inches. The insulation sheath 40 has anouter diameter of approximately 0.03 inches and an inner diameter ofabout 0.025 inches. The electrode guide tube 41 has an inner diameter ofabout 0.039 inches. It is to be appreciated that the above dimensionsare illustrative, and are not intended to be restrictive, as otherdimensions can be used depending in whole or in part, on the intendedapplication of the device.

Referring to FIGS. 3 and 4, the imaging device 16 disposed inside theelongated housing 12 includes a illumination region 44 and a viewingregion 42. Both regions 42 and 44 can include a plurality of opticalfibers 46 extending from the proximal end to the distal end of theelongated housing 12. In the embodiment of FIGS. 3 and 4, theillumination region 44 includes a plurality of optical fibers 46 incommunication with a light source (not shown) at a proximal end. Theplurality of optical fibers 46 surrounds the viewing region 42. Theviewing region 42 can include a fused bundle of optical fibers 48 incommunication with an objective lens 50 at the distal end for focusingan image. An example of the objective lens 50 is a gradient index(GRIN-self) objective lens having a diameter of about 0.039 inches. Theillumination region 44 and the viewing region 42 may be arranged inother ways and may comprise optical components other than or in additionto those described above. In other embodiments, other imaging devicescan be used for viewing the area of tissue in question. In oneembodiment, the imaging device 16 is surrounded by an outer sheathcomprising a polymeric material 47. In another embodiment, the imagingdevice 16 is disposed inside the elongated housing 12 without an outersheath. In one detailed embodiment, the imaging device 16 has a viewingangle 13 of about 70 degrees, as shown in FIGS. 1 and 2. It is to beappreciated that the viewing angle 13 can be greater or less than 70degrees depending in whole or in part, on the intended application ofthe device.

Referring to FIGS. 1 and 4, the deflection system 18 controllablydeflects the deflectable segment 22 by an angle of up to 180 degrees inone direction and 180 degrees in the opposite direction with respect tothe longitudinal axis of the elongated housing 12. In one embodiment,the deflection system 18 includes a flexible wire 54 extending from theproximal end to the distal end of the elongated housing 12 and a flatspring 56 in communication with the flexible wire 54 disposed at thedistal end of the elongated housing 12. The proximal end of the flexiblewire 54 is in communication with a steering mechanism 52, shown in FIG.1A as mounted on the handle 32. The steering mechanism 52 can pull theflexible wire 54 and cause the flat spring 56 to gradually deflecttoward a direction to which the wire 54 is pulled. Details of thesteering mechanism are described in U.S. Pat. No. 5,273,535, which isincorporated herein by reference. In one detailed embodiment, thedeflection system 18 has an outer diameter of approximately 0.02 inches.It is to be appreciated that the diameter of the deflection system 18can vary depending in whole or in part, on the intended application ofthe device.

Referring to FIGS. 5A-5E, in another embodiment, the deflectableinterstitial ablation device 10 further includes a driver 75 located inthe handle 32 and coupled to the electrode 14 for kinetically deployingthe electrode 14. In this embodiment, the electrode 14 can be a needleelectrode having a sharpened tip. The driver 75 exerts a forcesufficient to deploy the electrode 14 from inside the elongated housing12 to a position beyond the distal end of the elongated housing 12 in asingle motion. In one embodiment, the force of deployment can range fromabout ¼ lb to about 1 lb. A force in this range is sufficient to causethe electrode 14 to penetrate the urethral wall in a single motion.Kinetic deployment which permits sudden and high speed deploymentfacilitates electrode penetration through the urethral wall, reducingpatient discomfort and improving the accuracy and control of needledeployment. In the present embodiment, such kinetic deployment isachieved by employing a driver 75 comprising a spring-operated actuatingmechanism.

Referring to FIG. 5A, the handle 32′ includes slots 60 and 61 havinglevers 62 and 63, respectively, and a recess 64 having an actuator 66 onan outer surface of the handle 32′. Referring to FIGS. 5B to 5E,contained within the housing 32′ are slide members 68 and 69. The slidemember 68 is connected to the insulation sheath 40, and the slide member69 is connected to the electrode 14. The lever 62 is connected to theslide member 68 and the lever 63 is connected to the slide member 69.Reduced proximal sections 70 and 71 of the slide members 68 and 69 arereceived within spring coils 72 and 73, respectively. The actuator 66 isoperatively coupled to the slide member 69. In this embodiment, theelectrode 14 and the insulation sheath 40 are sequentially propelled.

Referring to FIG. 5C, prior to inserting the elongated sheath 12 insidethe body, the device 10 is loaded by pulling the levers 62 and 63 in theproximal direction. As the lever 62 is pulled in the proximal direction,a projection 74 on the slide member 68 slides over and catches thedistal surface of a catch or stop 76, and as the lever 63 is pulled, aprojection 78 of the slide member 69 catches on a stop 80. Once theelongated sheath 12 is properly placed inside the body and thedeflectable segment 22 is deflected by a desired angle, the needleelectrode 14 and the insulation sheath 40 are deployed by pulling theactuator 66 proximally and then down.

Referring to FIG. 5D, as the actuator 66 is pushed down, the stop 76moves allowing the slide member 69 to move distally until the projection78 is restrained by a stop 82. The needle electrode 14 is propelledforward as the sliding member 69 is moved by the force from the coiledspring 73. Referring to FIG. 5E, as the slide member 69 moves forward,and just before the end of its distal movement as the projection 78reaches the stop 82, a trigger member 86 on the slide member 69 contactsa release member 88. Movement of the release member 88 causes theprojection 74 to disengage from the stop 76, such that the slide member68 is propelled forward by the force of the coiled spring 73. As theslide member 68 propels forward, the insulation sheath 40 propels beyondthe distal end of the elongated housing 12 covering a pre-determinedportion of the needle electrode 14.

Referring to FIG. 5D, in one embodiment, only the needle electrode 14 ispropelled with a spring operated actuating mechanism, while theinsulation sheath 40 is glided over the needle electrode 14. Once theneedle electrode 14 has penetrated the urethral wall, gliding theinsulation sheath 40 over the needle electrode 14 can be easily achievedwithout causing much discomfort to the patient.

In one embodiment, depth of needle electrode 14 penetration iscontrollable, such that different locations within the prostate can bereached by the needle electrode 14. In one detailed embodiment, thesteering mechanism 52 described above can provide depth control. Fordeeper penetration, the electrode 14 tip can be deflected closer to 90degrees, whereas for shallow penetration, the needle electrode 14 tipcan be deflected by a smaller angle, such as, for example, 45 degrees.In another detailed embodiment, depth of electrode 14 penetration isadjustable using a slide member on the handle 32, which controlsmovement of the needle electrode 14 relative to the elongated housing12. In this embodiment, maximum penetration depth may be fixed byplacing a stop inside the handle 32.

Referring to FIG. 6, in another embodiment, the electrode 14 can bekinetically deployed using a foot pedal. As shown, the interstitialablation system 89 includes a foot pedal 90, a control and power sourcemodule 92, an actuator, a light source 98, the deflectable interstitialablation device 10, and a return electrode 91. The light source 98supplies light to the illumination region 44 of the imaging device 16,described above in FIGS. 3 and 4. As shown in this embodiment, thereturn electrode 91 is placed on the patient 110. The foot pedal 90 iscoupled to the control and power source module via a cable 94, and thecontrol and power source module 92 is coupled to the actuator 96 via acable 99. In operation, a physician performing an ablation procedureproperly places the ablation device 10 inside the patient's body, thensteps on the foot pedal 90 to deploy electrode 14, leaving his or herhands free to perform other functions. Additional features such asapplication of fluid to a treatment site, application of energy to theelectrode 14, and the triggering temperature measurement means at thedistal end of the electrode 14 may also be activated using the pedal 90.In one embodiment, the interstitial ablation system 89 can includeseveral foot pedal actuators for performing each of these functions. Inanother embodiment, the interstitial ablation system 89 can include onlyone foot pedal used to activate multiple functions. In this embodiment,the control module 92 may be programmed to control the order of theperformance of each function.

Referring to FIG. 7, shown is the actuator 96 which controls electrodedeployment. In the present embodiment, the actuator 96 can comprise asolenoid 100. As shown, the solenoid 100 is coupled to the control andpower module 92 at a proximal end via a cable 105, and coupled to theproximal end of the electrode 14 at a distal end via a luer fitting 104.The actuator 100 is held within an actuator housing 102, which iscoupled to the luer fitting 104. The luer fitting 104 is sized andshaped to attach to the proximal end of the elongated housing 12 of thedeflectable interstitial ablation device 10. Alternatively, the luerfitting 104 may be sized and shaped to attach to a working channel of aflexible cystoscope for those applications in which cystoscopes areused. When the foot pedal 90 is depressed, current from the power source92 is applied to the solenoid 100, which forces the electrode 14 todeploy beyond the distal end of the elongated housing 12. Other types ofactuators such as a rotary motors and linear motors, as well as otherelectromechanical devices can be used to perform these functions aswell. It is to be appreciated that, a number of foot pedals andactuators for activating a mechanical event can be interchangeably usedto actuate the electrode 14, or provide fluid delivery and temperaturesensing at the treatment site.

The deflectable interstitial ablation device 10 of the inventionprovides many other features typically performed in ablation procedures.As briefly described above, the deflectable interstitial ablation device10 can be coupled to a fluid source to permits delivery of fluid to thehousing 12 or to an internal bore (not shown) formed in the electrode 14such that fluid is dispensed near the treatment site for providingcooling or for enhancing ablation. In such an embodiment, the fluid, canbe for example, an electrolytic fluid which increases the ablation area,or a fluid that provides therapeutic effects. In another embodiment, theelongated housing 12 can include a separate passageway suitable forfluid delivery. In both embodiments, fluid can be introduced through theluer port 36 (FIG. 1A). In another embodiment, the solenoid can becoupled to a syringe for introducing fluid inside the elongated housing12. Application of current to the solenoid in this case would cause thesyringe to discharge the fluid held within a fluid source into theelongated housing 12.

In another embodiment, the deflectable interstitial ablation device 10can include a temperature sensing system for measuring tissuetemperature during the ablation procedure. In one detailed embodiment,the temperature sensing system can include a thermocouple disposed nearthe distal end of the electrode 14, such as by being fixed at the distalend of the insulation sheath 40 that is fixed to the electrode 14. Instill another embodiment, the device 10 can include an impedancemonitoring system in communication with the proximal end of theelectrode 14. The impedance monitoring system can measure impedance nearthe distal end of the electrode 14. The interstitial ablation device canfurther employ a feedback system that uses the temperature and or theimpedance data to control the delivery of RF energy to the electrode 14.The control module 92 can, for example, include means for automaticallyadjusting the magnitude and duration of the ablation energy delivered tothe electrode in response to one or both of these parameters. Theinterstitial ablation system can also include a safety feature whichcuts off the delivery of energy when the temperature or the impedancevalue exceeds a threshold value.

The deflectable interstitial ablation device 10 of the present inventiondoes not require the use of an endoscope and therefore can be entirelydisposable. The disposable device can attach to reusable eye piece andother equipment such as a light source, and a control and power sourcemodule. In an alternative embodiment, the imaging system 16 can beremoved from the device 10 for subsequent reuse.

As shown and described, the present invention features an improvedtransurethral interstitial ablation apparatus and method for performingtransurethral ablation. While the invention has been particularly shownand described with reference to specific preferred embodiments, itshould be understood by those skilled in the art that various changes inform and detail may be made therein without departing from the spiritand scope of the invention as defined by the appended claims.

1. A deflectable interstitial thermal treatment device, comprising: anelongated housing having a proximal end, a distal end, and a deflectablesegment; an electrode mounted within the elongated housing anddeployable from a first position within the elongated housing to asecond position a predetermined distance beyond the distal end of theelongated housing, the electrode having a flexible portion capable ofdeflecting with the deflectable segment of the elongated housing; remotemeans for activating deployment of the electrode; and a deflectionsystem disposed within the elongated housing controlled by ahandle-operable steering mechanism for controllably deflecting thedeflectable segment of the elongated housing by any angle with respectto a longitudinal axis of the housing, the deflection system having aproximal end in communication with the handle-operable steeringmechanism.
 2. The medical device of claim 1, wherein the deflectablesegment deflects at an angle between 0 degrees and 180 degrees withrespect to a longitudinal axis of the elongated housing.
 3. The medicaldevice of claim 1, wherein the deflectable segment deflects at an anglebetween 90 and 180 degrees with respect to the longitudinal axis of theelongated housing.
 4. The medical device of claim 1, wherein the remotemeans comprises a foot pedal.
 5. The medical device of claim 1, whereinthe electrode is surrounded by an insulation sheath.
 6. The medicaldevice of claim 5, wherein the insulation sheath comprises a polymericmaterial.
 7. The medical device of claim 5, wherein the insulationsheath covers the proximal portion of the electrode extending beyond thedistal end of the elongated housing.
 8. The medical device of claim 1,further comprising a control system in electrical communication with aproximal end of the electrode.
 9. The medical device of claim 8, furthercomprising a power source in communication with the control system. 10.The medical device of claim 9, wherein a foot pedal activates deliveryof energy from the power source to the electrode.
 11. The medical deviceof claim 1, wherein the elongated housing is in communication with ahandle.
 12. The medical advice device of claim 11, wherein the handlecomprises slots.
 13. The medical device of claim 12, wherein the slotscomprise levers.
 14. A method for treating tissue, comprising the stepsof: (a) inserting a deflectable interstitial thermal treatment deviceinto a body lumen which provides access to the tissue, the deflectableinterstitial thermal treatment device comprising: an elongated housinghaving a proximal end, a distal end, and a deflectable segment; anelectrode mounted with the elongated housing and deployable from a firstposition within the elongated housing to a second position apredetermined distance beyond the distal end of the elongated housing,the electrode having a flexible portion capable of deflecting with thedeflectable segment of the elongated housing; remote means foractivating deployment of the electrode; and a deflection system disposedwithin the elongated housing controlled by a handle-operable steeringmechanism for controllably deflecting the deflectable segment of theelongated housing by any angle with respect to a longitudinal axis ofthe housing, the deflection system having a proximal end incommunication with the handle-operable steering mechanism; (b)positioning the distal end of the elongated housing near the tissue; (c)deflecting the deflectable segment of the elongated housing toward thetissue; (d) deploying the electrode to a position a distal end of theelectrode adjacent the tissue; and (e) applying an energy to theelectrode in an amount and for a duration sufficient to thermally treatthe tissue.
 15. The method of claim 14, wherein the tissue is prostatetissue.
 16. The method of claim 14, wherein the remote means foractivating deployment of the electrode comprises the stepping on a footpedal.
 17. The method of claim 16, wherein the electrode is covered byan insulation sheath.
 18. The method of claim 17, wherein the insulationsheath covers a proximal portion of the electrode extending beyond thedistal end of the elongated housing.
 19. The method of claim 17, whereinthe insulation sheath is extended over the proximal portion of theelectrode, thereby preventing the electrode from touching the walls ofthe lumen during insertion of the medical device.
 20. The method ofclaim 16, wherein the electrode penetrates a wall of the lumen whendeployed.